Does Vi, Destructive ability I can use it as often as I want?

Yes — Vi, Destructive's ability can be used as many times per turn as you can pay for it, since nothing on the card limits the number of activations.

Each activation costs 1 card recycled from your trash, so the only limit is how many cards you have in trash (Rule 416.3). Activate once, let it resolve, then do it again — each activation resolves individually and gives +1 Might this turn.

One restriction: this is an activated ability, so it can only be used on your turn, in an Open State (empty chain, no showdown), and your opponent gets a chance to respond between each activation (Rule 381; FAQ #8013). You can't use it at action/reaction speed or during a showdown.